<!DOCTYPE html>
<meta charset="UTF-8">
<style>
.parent {
  --length-percentage: 40%;
}
.target {
  --length-percentage: 10px;

  /* Testing ems. */
  font-size: 20px;
}
</style>
<body>
<script src="../interpolation/resources/interpolation-test.js"></script>
<script>
CSS.registerProperty({
  name: '--length-percentage',
  syntax: '<length-percentage>',
  initialValue: 'calc(40px + 80%)',
  inherits: false,
});

assertInterpolation({
  property: '--length-percentage',
  from: neutralKeyframe,
  to: '20px',
}, [
  {at: -0.3, is: '7px'},
  {at: 0, is: '10px'},
  {at: 0.5, is: '15px'},
  {at: 1, is: '20px'},
  {at: 1.5, is: '25px'},
]);

assertInterpolation({
  property: '--length-percentage',
  from: 'initial',
  to: '40%',
}, [
  {at: -0.3, is: 'calc(52px + 92%)'},
  {at: 0, is: 'calc(40px + 80%)'},
  {at: 0.5, is: 'calc(20px + 60%)'},
  {at: 1, is: '40%'},
  {at: 1.5, is: 'calc(-20px + 20%)'},
]);

assertInterpolation({
  property: '--length-percentage',
  from: 'inherit',
  to: '20px',
}, [
  {at: -0.3, is: 'calc(-6px + 52%)'},
  {at: 0, is: '40%'},
  {at: 0.5, is: 'calc(10px + 20%)'},
  {at: 1, is: '20px'},
  {at: 1.5, is: 'calc(30px + -20%)'},
]);

assertInterpolation({
  property: '--length-percentage',
  from: 'unset',
  to: 'calc(20px + 40%)',
}, [
  {at: -0.3, is: 'calc(46px + 92%)'},
  {at: 0, is: 'calc(40px + 80%)'},
  {at: 0.5, is: 'calc(30px + 60%)'},
  {at: 1, is: 'calc(20px + 40%)'},
  {at: 1.5, is: 'calc(10px + 20%)'},
]);

assertInterpolation({
  property: '--length-percentage',
  from: '-10px',
  to: '10px',
}, [
  {at: -0.3, is: '-16px'},
  {at: 0, is: '-10px'},
  {at: 0.5, is: '0px'},
  {at: 1, is: '10px'},
  {at: 1.5, is: '20px'},
]);

assertInterpolation({
  property: '--length-percentage',
  from: '10em',
  to: '20em',
}, [
  {at: -0.3, is: '140px'},
  {at: 0, is: '200px'},
  {at: 0.5, is: '300px'},
  {at: 1, is: '400px'},
  {at: 1.5, is: '500px'},
]);

assertInterpolation({
  property: '--length-percentage',
  from: '10em',
  to: '100px',
}, [
  {at: -0.3, is: '230px'},
  {at: 0, is: '200px'},
  {at: 0.5, is: '150px'},
  {at: 1, is: '100px'},
  {at: 1.5, is: '50px'},
]);

assertInterpolation({
  property: '--length-percentage',
  from: '10em',
  to: '100%',
}, [
  {at: -0.3, is: 'calc(260px + -30%)'},
  {at: 0, is: '200px'},
  {at: 0.5, is: 'calc(100px + 50%)'},
  {at: 1, is: '100%'},
  {at: 1.5, is: 'calc(-100px + 150%)'},
]);
</script>
</body>
